Can you Export edited textures out of Blender?
Referring to what you have told in the question , i am assuming that you have an image texture , you did something to it , and now you want to take it out as another image, well thats called texture baking , what you need to do is to open the image editor (i hope you know how to )

and then in your node tree , Add an image texture and create a new image , name it whatever you want and DONT connect it to anything.Then Switch to cycles renderer , apply the material to a plain and then in the render settings , go to bake , and give it a Diffuse Bake , Not combined bake. Then you will see in the image editor , that your black image has turned into the result of your node tree. Click on image&gt;Save as to export it as a jpeg or png.